title: Intestinal salivary, and tonsillar IgA and J-chain production in a patient with severe deficiency of serum IgA.
abstract: An 18-year-old man with tendency to respiratory infections had a serum IgA level of only 2% of normal whereas his salivary IgA amounted to 50% of the lower normal concentration range. Moreover, both the rectal and jejunal IgA-producing cell populations were of normal size. Nevertheless, a relative increase of salivary IgM and a distinctly raised number of IgM-producing cells in jejunal mucosa indicated an imbalance in his secretory immune system. This possibility was supported by the presence of an excess of J 3 chains in most of his intestinal IgA immunocytes, probably reflecting a reduced synthetic rate of IgA. The number of tonsillar IgA-producing cells was only slightly below the normal range; most of them lacked J chain, as normal, and could thus be a source of his serum IgA, which was mainly monomeric. A marked deficiency of IgA-producing cells in his bone marrow supported the notion that this tissue site normally is the major source of monomeric IgA. This study suggests that a generally defective IgA system may be topically activated owing to the persistent antigenic and mitogenic load on mucosa-associated lymphoid tissues. Our findings are not consistent with a general regulative compartmentalization of monomer- and dimer-producing IgA immunocyte populations.
mesh_terms: D000293:Adolescent; D000921:Antibody-Producing Cells / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology; D001853:Bone Marrow / Q000276:immunology; D004406:Dysgammaglobulinemia / Q000276:immunology*; D005455:Fluorescent Antibody Technique; D006801:Humans; D017098:IgA Deficiency; D007070:Immunoglobulin A / Q000032:analysis; D007071:Immunoglobulin A, Secretory / Q000032:analysis; D007144:Immunoglobulin J-Chains / Q000032:analysis*; D007583:Jejunum / Q000276:immunology; D008213:Lymphocyte Activation; D008297:Male; D008934:Mitogens / Q000494:pharmacology; D014066:Palatine Tonsil / Q000276:immunology; D012463:Saliva / Q000276:immunology
chemical_list: D007070:Immunoglobulin A; D007071:Immunoglobulin A, Secretory; D007144:Immunoglobulin J-Chains; D008934:Mitogens